2020 Tropical Cyclone Season Outlook West Pacific, Atlantic, and East & Central Pacific Basins
Decision Support for Weather Sensitive Operations Your Presenter Today
Chris Hebert Manager, TropicsWatch [email protected] @TropicsWatch
Chris has been forecasting tropical cyclones worldwide for 40 years. In Today’s Presentation
• Global Seasonal Activity
• Northwest Pacific Typhoon Climatology
• 2019 Northwest Pacific Typhoon Outlook
• Indian Ocean Dipole Impacts on NW Pacific and North Indian Ocean Cyclones
• 2020 Northwest Pacific Typhoon Season Outlook
• Atlantic Basin 2019 Outlook / 2020 Hurricane Season Outlook
• East & Central Pacific Hurricane Season Outlook A few years ago, we made of study of seasonal activity around the globe – April and May are the quietest months, in general
Northern Hemisphere Peak Season
Southern Hemisphere Peak Season Northwest Pacific is the Most Active Basin in the World Tropical Cyclones Can Form Year-Round
All Tropical Cyclones 1980-2019 About 30% of all tropical cyclone activity worldwide forms in the northwest Pacific. Average Monthly Northwest Pacific Tropical Cyclones (1950-2019)
3-4 per month
One every 3-5 years Our forecast for 2019 verified well, both in total numbers of named storms & typhoons as well as the primary cyclone paths
Risk Areas
Below Normal
30-yr Average Near Normal
26 Named Storms Above Normal 13 Typhoons
2019 Forecast 28 Named Storms (+) 15 Typhoons (+)
2019 Observed 29 Named Storms (+) 17 Typhoons (+) Primary Tracks Secondary Tracks 2019 Season was a little above normal for the NW Pacific. Our primary threat region (red shading) verified well
Normal Season 26 Named Storms 16 Typhoons
2019 Totals 29 Named Storms 17 Typhoons 2020 Season as of May 6 – No Tropical Cyclone Tracks A Quiet Start to the 2020 Typhoon Season Currently, warmer-than-normal water across much of the NW Pacific, including South China Sea
Above normal water temperatures in Tropical Pacific east of 160E is a signal for a more active typhoon season. This time last year, pocket of cooler water around Philippines, where typhoon activity was below-normal
Last season, warm water was concentrated north of 18N latitude, and that’s where the stronger typhoons tracked. Storms reaching the Philippines from the east tended to be weaker. (Positive Indian Ocean Dipole) The Indian Ocean Dipole (IOD) tracks the temperature differential between the eastern & western Indian Ocean
The positive phase (warm water in the west) is more The negative phase (warm water in the east) is common during a La Nina in the Tropical Pacific. more common during an El Niño in the Tropical Reduces tropical cyclone activity in the Bay of Pacific. Reduces tropical cyclone activity in the Bengal and the South China Sea. Arabian Sea, enhances activity in the South China http://www.bom.gov.au/climate/iod/ Sea. After a very strongly-positive IOD last Oct/Nov (warm water to west) , the IOD has trended toward neutral in recent months
13 Strongly-positive IOD in 2019 resulted in a very active cyclone season in the Arabian Sea
There were three intense tropical cyclones in the Arabian Sea in 2019 – Vayu, Kyarr, and Maha. Current IOD is in the “Neutral” phase does not significantly enhance or inhibit tropical cyclone activity in the North Indian Ocean or the Southwest Pacific Forecast is for continued neutral IOD into September, though bordering on a Negative IOD at times (slight enhancing factor for SW Pacific and Bay of Bengal)
Positive Phase – Warming West
Negative Phase – Warming East
http://www.bom.gov.au/climate/enso/#tabs=Indian-Ocean Wetter-than-normal weather July-September over South China Sea may mean more activity there this season
European model predicts enhanced rainfall over the South China Sea this season. This may increase the chances of typhoon activity in the region. Best chance of above-normal impacts into the Philippines and over the South China Sea
Risk Areas Below Normal
30-yr Average Near Normal
26 Named Storms Above Normal 13 Typhoons
2020 Forecast 28 Named Storms (+) 15 Typhoons (+) Primary Tracks
Primary Tracks Names for 2020 start with Vongfong and proceed downward through each column before starting at the next column
Vongfong Bavi Linfa Vamco In-fa
Nuri Maysak Nangka Krovanh Cempaka
Sinlaku Haishen Saudel Dujuan Nepartak
Hagupit Noul Molave Surigae Lupit
Jangmi Dolphin Goni Choi-wan Mirinae
Mekkhala Kujira Atsani Koguma Nida
Higos Chan-hom Etau Champi Omais The North Atlantic is the third most active basin in the world, ranking just behind the East & Central Pacific Our Forecast for the 2019 Season
Normal (past 30 yrs) 14 Named Storms 7 Hurricanes 3 Intense Hurricanes
Our Forecast 14 Named Storms 6 Hurricanes 2 Intense Hurricanes
2019 Totals 18 Named Storms 6 Hurricanes 3 Intense Hurricanes 2019 Season had above-normal activity, but with several weak, short-lived storms. Bahamas significantly impacted.
Normal (past 30 yrs) 14 Named Storms 7 Hurricanes 3 Intense Hurricanes
Our Forecast 14 Named Storm 6 Hurricanes 2 Intense Hurricanes
2019 Totals 18 Named Storms 6 Hurricanes 3 Intense Hurricanes Barry was a brief “pop up” hurricane that moved into the mid-Louisiana coast on July 13th
No deaths reported, though Barry produced $600 million in damage “Pop-up” hurricanes develop in Gulf once every 2 years Most pop-up hurricanes impact the Gulf lease areas
Pop-up hurricanes are those that originate in the Gulf of Mexico or over the northern Yucatan Peninsula and become hurricanes in the Gulf prior to landfall.
40 Hurricanes formed in the Gulf of Mexico over 80 seasons between 1940 and 2019 (including Barry 2019) Barry was unique – it formed from a non-tropical weather feature identified below in southwestern Kansas on Tuesday, July 2nd
Graphic from the NHC post-storm report on Barry Three days later, on Friday, July 5th, we indicated potential tropical development in the NE Gulf the following week.
No mention of development potential from the NHC that Friday
26 3:00 PM Monday, July 8th – 1st advisory issued on Disturbance 12 Predicted to move inland into south Louisiana noon Saturday
Advisory #1 – 3PM Monday Advisory #20 – 9AM Saturday
Landfall 1PM Saturday South of Landfall 9AM Saturday South of Lake Charles – wind 60 mph Lafayette – wind 70-75 mph It wasn’t until 10AM Thursday, when the NHC upgraded the system to Tropical Storm Barry, only 48 hrs before landfall
28 2020 Atlantic Hurricane Season Outlook
Decision Support for Weather Sensitive Operations Factors to consider…
• Water Temperatures in Tropical Pacific (El Niño or La Niña?)
• Water Temperatures in the Deep Tropics
• Atlantic Multi-decadal Oscillation (AMO)
• Strength of the Azores-Bermuda High (North Atlantic Oscillation – NAO)
• Analog Seasons Sea surface temperatures in Tropical Pacific have been above- normal for the past two seasons – that may be ending this season
Cooler Tropical Pacific waters would be less of a hindrance as far as Caribbean Sea & Gulf of Mexico tropical development International Research Institute’s (IRI) multi-model plot suggests cool-neutral for peak season (no El Niño) Current trend in the Tropical Pacific is for slow cooling
3-Day Change in Water Temperatures Water temperatures all across the Atlantic are above-normal at present. East Pacific is still warm, but slowly cooling.
28-Day Water Temperature Anomalies Ending April 26th Oceanic Heat Content is considerably higher this year, particularly in the central & western Caribbean
April 28, 2020 Oceanic Heat Content has increased considerably this year, particularly in the central & western Caribbean
April 28, 2019 Atlantic naturally warms & cools over periods of 25-40 years. Warm cycles produce 4 major hurricanes season (2 in a cool cycle). Atlantic shifted to a cool cycle in 2013 (we’re in a cool cycle as of March)
1969 1995 2013 Warm – 1926-1969 Warm – 1995-2013?
Cool – 1970-1994 Cool March 2013-???? However, the AMO is weighted heavily toward northern latitudes, where the water is currently quite cool. Typically, when water is cool up north it is also cool between Africa & the Caribbean – Not this year, though.
Cooler Water
Very Warm Water
Warm Water
Warm Water European model is predicting near normal rainfall across the Deep Tropics August-September (favorable environment)
Near Normal Updated analog years now favor an active North Atlantic hurricane season There were 8 hurricane strikes on the U.S. in the 4 analog years with a high incidence of Cuba and Southern Yucatan landfalls
41 Most signals now point to an active hurricane season
More Active Season Less Active Season
• No El Niño this season • Cool phase of Atlantic Multi-Decadal Oscillation? (this is questionable) • Above-normal water temperatures & Oceanic Heat Content in Tropical Atlantic, Caribbean, & Gulf
• Analog years support an active hurricane season
• More liberal naming convention by the National Hurricane Center Our Forecast is for Above-Normal Activity
Normal (past 30 yrs) 14 Named Storms 7 Hurricanes 3 Intense Hurricanes
Our Forecast 16 Named Storms 8 Hurricanes Potential Tracks 4 Intense Hurricanes
Risk Areas Below Normal Potential Tracks Near Normal Above Normal Names for 2020 – same list as 2008 and 2014
Arthur Hanna Omar
Bertha Isaias Paulette
Cristobal Josephine Rene Three of the names are replacements for the Dolly Kyle Sally retired Gustav, Ike, and Paloma, all in 2008. Edouard Laura Teddy
Fay Marco Vicky
Gonzalo Nana Wilfred 2020 Hurricane Season Outlook for Central and East Pacific
Decision Support for Weather Sensitive Operations East Pacific is the second most active basin, many hurricanes threaten shipping lane along the west coast of Mexico
All East & Central Pacific Storms (1980-2005) Activity this season is predicted to be near normal or slightly below- normal for the Central and East Pacific this season. Slightly below- normal threat for Hawaii, normal threat west coast of Mexico
Risk Areas Our Forecast Below Normal 18 Named Storms Near Normal 9 Hurricanes Above Normal 4 Intense Hurricanes East Pacific Names for 2020 Central Amanda Iselle Rachel Pacific
Boris Julio Simon Hone
Cristina Karina Trudy Iona
Douglas Lowell Vance Keli
Elida Marie Winnie Lala
Fausto Norbert Xavier Moke
Genevieve Odalys Yolanda Nolo
Hernan Polo Zeke Olana 2020 Tropical Cyclone Season Outlook West Pacific, Atlantic, and East & Central Pacific Basins
Decision Support for Weather Sensitive Operations